Answer : The final volume of a gas is, 
Explanation :
According to the Charles's law, the volume of a gas is directly proportional to the temperature of the gas at constant pressure and the number of moles of gas.

or,

where,
= initial volume of gas = 
= final volume of gas = ?
= initial temperature of gas = 491 K
= final temperature of gas = 297 K
Now put all the given values in the above formula, we get the final volume of a gas.


Therefore, the final volume of a gas is, 